Starfish move using a water vascular system. When water comes into the system, it is then circulated from the stone canal to the ring canal and into the radial canals. The radial canals carry water to the ampulla portion of the tube feet. Each tube foot consists of an internal ampulla and an external podium When the ampulla is squeezed, it forces water into the podium. The tube feet latch on to surfaces and move in a wave, with one body section attaching to the surfaces as another releases.